Marketable Pod Yield Research Articles

Studies on Genetic Divergence in Faba Bean (Vicia faba L.)

Background: The genetic divergence in faba bean genotypes is critical for breeding programs aiming to improve yield and other agronomic traits. Understanding the extent of genetic variability among different genotypes can guide the selection of superior varieties and enhance crop improvement efforts. This study was conducted to evaluate the genetic diversity among 47 faba bean genotypes grown under the specific agro-climatic conditions of Chhattisgarh. Methods: The experiment was conducted during the Rabi season of 2022-23 at the Hi-Tech-Nursery, Dau Kalyan Singh College of Agriculture and Research Station, Bhatapara, under Indira Gandhi Krishi Vishwavidyalaya, Chhattisgarh. A total of 47 faba bean genotypes were evaluated for genetic divergence using Mahalanobis D2 statistics and Tocher’s method. Ten quantitative characters, including marketable pod yield per plant and marketable pod weight appearance, were measured and analyzed. The genotypes were grouped into clusters based on their genetic distances. Result: The clustering pattern indicated that genetic diversity was independent of geographical diversity. Cluster II contained the highest number of genotypes (19), followed by Cluster I (13), while Cluster IV had the least (1). Among the ten quantitative characters studied, marketable pod yield per plant contributed most to genetic divergence, followed by marketable pod weight appearance. The maximum intra-cluster D2 value was observed in Cluster IV (477.35), followed by Cluster III (250.07). The highest inter-cluster D2 value was between Cluster I and Cluster IV (7917.34), followed by Cluster IV and Cluster V (6156.43).

Yield Response of Abelmoschus Esculentus as Influenced by Compost With Tithonia Leaves

Tithonia diversifolia is a genus of flowering plants and its leaves have been used to improve fertility and soil properties by supplying organic matters and nutrients. This experiment was done to study the effect of compost with powdered Tithonia leaves on okra yield and to select the optimal quantity of Tithonia leaves for obtaining the optimum yield of okra in the sandy regosol soil conditions. This experiment was carried out in a completely randomized design with five replicates with the following treatments; T1 - recommended chemical fertilizers (control), T2 - compost 140 g alone, T3 - compost 140 g + 15 g powdered Tithonia leaves (PTL), T4 - compost 140 g + 30 g PTL, T5 - compost 140 g + 45 g PTL, T6 - compost 140 g + 60 g PTL. These fertilizers were applied as the basal application to each polybag (0.07 m2), while the top dressing was not applied in this experiment. The results revealed that compost with PTL application had effects on the number of pods per plant, the number of seeds per pod, pod length, pod girth, single pod weight, fresh pod weight per plant and marketable pod yield. Further, it was found that T4 was more suitable for obtaining a better marketable pod yield of okra in sandy regosol soil conditions. Based on the results obtained, it can be concluded that 2 kg m-2 compost with 0.43 kg m-2 powdered Tithonia leaves as the basal application could be used in okra cultivation.

Influence of Farmyard Manure and NPS Fertilizer on Hot Pepper (Capsicum annuum L.) Growth and Yield Variables at Western Ethiopia

Hot peppers are important vegetable crops widely grown in Ethiopia. Investigation into the economic, nutritive and therapeutic purposes of the pepper plant is extremely limited. Thus, a field trial was piloted to assess the influence of NPS (compound fertilizer containing three important plant nutrients of nitrogen, phosphate, and sulphur with the ratio of 19% N, 38% P2O5, and 7% S) and farmyard manure (FYM) fertilizer on hot pepper at the Dambi Dollo University research field for two consecutive years (2020 and 2021) under rain fed. The finding was systematized in a Randomized Complete Block Design (RCBD) with three repetitions and variety of Marako Fana hot pepper was assessed. NPS fertilizer at four level (0, 100, 200, 300 kg N ha-1) and four FYM levels (0, 2.5, 5, 7.5, 10 t ha-1) were owed to the study area and a total of 20 treatments. The research results revealed that FYM and NPS mineral fertilizer interacts to affect positively (P<0.05) maximum parameters without unmarketable harvest, which was influenced through the single effect of NPS and FYM. The highest marketable pod yield (2.28 t ha-1) and total pod harvest (2.72 t ha-1) was recorded through NPS rates of 100 kg ha-1 applied with 5 t ha-1 of farmyard manure. Consequently, it is likely to determine that hot pepper farmers can use NPS mineral fertilizer rate of 100 kg ha-1 with 5 t ha-1 of FYM that would expand yield of the hot peppers in the study area with similar agro-ecological conditions.

Exogenous Application of Organic and Inorganic Nutrients and Their Impact on Agronomical Traits, Yield and Quality of Vegetable Cowpea [Vigna unguiculata (L) Walp

The study was undertaken on heavy black soil at Regional Horticulture Research Station, Navsari Agricultural University, Navsari, Gujarat (India) in order to analyze the effect of foliar application of organic and inorganic nutrients on growth, yield and quality of vegetable cowpea. The field was thoroughly ploughed and harrowed followed by land levelling using wooden plank. Basal dose of manure and fertilizer of 20:40:00 kg ha-1 was incorporated in the soil during land preparation. The seeds were planted 45 cm between rows and 30 cm between plants laid out in a Randomized Complete Block Design with nine treatments replicated three times. Treatments were as follows: Control (T1), 2% Panchagavya (An organic solution made from cow dung, cow urine, cow butter, cow curd and cow milk) (T2), 3% Panchagavya (T3), 0.5% Novel plus organic liquid nutrients (T4), 1% Novel plus organic liquid nutrients (T5), 1.5 % Novel plus organic liquid nutrients (T6), 0.5% Micronutrient grade IV (T7), 1% Micronutrient grade IV (T8) and 1.5% Micronutrient grade IV (T9). The observations were made at the intervals of 60 and 90 DAS and data was collected on plant growth, yield and quality parameters. Results showed that the application of 1% Novel plus organic liquid nutrients (NOVEL) (T5) exhibited maximum plant height (35.73 and 56.93 cm, respectively), number of leaves per plant (39.27 and 52.73, respectively) at 60 and 90 days after sowing (DAS) and increased leaf area (162.14 cm2). Substantial effect of foliar application of 1% Novel plus organic liquid nutrients (NOVEL) (T5) was detected in yield parameters viz., number of clusters per plant (12.07), number of pods per plant (58.00), marketable pod yield (6.04 kg/plot). Furthuer to this, 1% Novel plus organic liquid nutrients indicated notable effect on protein content of pods (24.04%), iron (Fe) content (220.12 ppm) and zinc (Zn) content (62.76 ppm) of cowpea pods at final harvest. Novel Plus organic liquid nutrient can play a major role in growth, yield and quality in vegetable cowpea production.

Efficacy of Acaricides against Red Spider Mite <i>Tetranychus urticae</i> Infesting Yard Long Bean

Field experiments were carried out at Zonal Agricultural and Horticultural Research Station, Navile, Keladi Shivappa Nayaka University of Agricultural and Horticultural Sciences, Shivamogga, Karnataka India during kharif 2020 and 2021. A total of seven acaricides were evaluated, and the results revealed that spiromesifen 22.9SC @ 0.8 ml/ l was the most effective in reducing mites (87.21% reduction) followed by diafenthiuron 50WP @ 1.0 gm/ l (84.49%). Maximum marketable pod yield was obtained with spiromesifen 22.9SC (21.36 t/ ha) and it was closely followed by diafenthiuron 50WP (20.15 t/ha). Maximum cost benefit ratio was observed with these, and thus spiromesifen 22.9SC @ 0.8 ml/ l and diafenthiuron 50WP @ 1.0 g/ l can be recommended against mites in yard long bean.

Effect of Conjoint Application of Inorganic and Organic Nutrient Sources on Yield and Economics of French Bean (Phaseolus vulgaris L.)

Background: French bean is an important legume vegetable crop. Due to its low ability to fix atmospheric nitrogen, excess amount of nitrogenous fertilizers are required by this crop as compared to other legumes. Overwhelming application of inorganic inputs has severely impacted environment and soil. So, there is a need to reduce inorganic inputs by adding organic nutrient sources. Methods: A three-year field experiment was laid comprising of eight treatment combinations and was replicated thrice during Kharif season of 2018, 2019 and 2020. Seeds of French bean cv. Green Wonder were sown at a spacing of 45 × 15 cm in each plot of size 3.0 m × 1.8 m. Recommended dose of fertilizers (NPK 50:100:50 kg ha-1) was followed as per different treatment details. Result: Application of 75 per cent NPK through inorganic and 25 per cent N through vermicompost resulted in minimum days to first pod harvest (61.89 days), maximum pod width (7.67 mm), number of pods per plant (30.96), plant height (51.29 cm), average pod weight (5.70 g), marketable pod yield (130.53 q ha-1) and highest benefit cost ratio (2.18) along with maximum net returns (Rs. 313061.43 ha-1).

Economically Optimal Plant Density for Machine-harvested Edamame

Consumer demand for edamame [Glycine max (L.) Merr.], the vegetable version of soybean (Glycine max), has grown during the past decade in North America. Domestic production of edamame is on the rise; however, research to guide fundamental crop production practices, including knowledge useful for developing appropriate recommendations for crop seeding rate, is lacking. Field experiments near Urbana, IL, were used to quantify edamame response to plant density and determine the economically optimal plant density (EOPD) of machine-harvested edamame. Crop growth and yield responses to a range of plant densities (24,700 to 395,100 plants/ha) were quantified in four edamame cultivars (AGS 292, BeSweet 292, Gardensoy 42, and Midori Giant) across 2 years. Plots were harvested with the Oxbo BH100, a fresh market bean harvester. In general, as plant density increased, branch number and the ratio of pod mass to vegetative mass decreased, while plant height and leaf area index increased. Recovery, the percent of marketable pods in the machine-harvested sample, varied among cultivars from 86% to 95%. Results identified the EOPD for machine-harvested edamame ranged from 87,000 to 120,000 plants/ha. When considering the effect of plant density on plant morphology, as well as seeding cost, harvester efficiency, recovery, and marketable pod yield, edamame EOPDs are considerably lower than seeding rates of up to 344,200 seeds/ha recommended in recent publications.

Quality of Snap Bean (Phaseolus Vulgaris L.) as influenced by N and P Fertilizer Rates at Jimma Southwestern Ethiopia

Snap bean is a warm-season crop harvested for its immature seed pods. In Ethiopia its production increased from time to time for both export and local markets. A field experiment was conducted at the research field of JUCAVM, during 2017 cropping season using irrigation aiming to improve the quality of snap bean. Five levels of N (0, 41, 82, 123, and 164 kg ha−1) and four levels of P (0, 46, 92 and 138 kg ha−1) were laid down in a randomized complete block design with three replications. N was applied in two equal splits (50% at planting and 50% during flowering) as Urea and the entire dose of P was applied basal as triple super phosphate at sowing. In this experiment pod length, pod diameter, pod protein concentration, pod straightness and marketable pod yield were measured as quality parameters. The results revealed that the main effects of N and P fertilizer rates showed significant differences (P ≤ 0.05) for all quality parameters except for percentage of pod protein concentration and straightness of pod. Accordingly, the interaction effects of N and P were significant for percent of pod protein concentration and straightness of pod. Considering the major quality parameters and marketable pod yield applying 82 kg N ha −1 and 46 kg P2O5 ha−1 gave better result to increase the quality of snap bean in Jimma area. However, repeating the experiment for more seasons and similar location would help us draw sound conclusion and recommendations.

Yield and Yield Components of Snap Bean (Phaseolus vulgaris L.) as affected by N and P Fertilizer Rates at Jimma, Southwestern Ethiopia

Snap bean is one of the newly introduced legume crops in Ethiopia and it is an important crop in the provision of food security and earing forging currency. It responds much better to the application inorganic fertilizer especially N and P fertilizers due to lack of nodule forming bacteria in the soil and low in building of fertile soil. However, information concerning the production package of snap bean at Jimma was scares and due to this there is limited evidence in the response of snap bean to inorganic fertilizers (N and P fertilizers) which can increase yield and quality. Cognizant to this fact, the experiment was conducted to realize the effect N and P fertilizers rates on yield and yield components of snap bean at Jimma, Southwestern Ethiopia. The experiment consisted of two factors, five levels of N (0, 41, 82, 123, and 164 kg/ha) and four levels of P (0, 46, 92 and 138 kg/ha) arranged 5 × 4 in randomized complete block design with three replications. N as urea was applied in split application (50% at sowing and 50% at flowering) whereas the full dose of P was applied at sowing as triple super phosphate. There was a significant difference (P ≤ 0.05) for main effects of N and P fertilizer rates for all yield and yield component variables. Out of the whole variables tap root length were significant by the interaction effects of N and P fertilizers rate. The result showed that the maximum marketable pod yield was obtained from 123 kg/ha N and 92 kg/ha P2O5 fertilizer application rates. While, the minimum marketable pod yield was recorded from the application of 0 N and P fertilizer rate. So, form this experiment application of 123 kg/ha N and 92 kg/ha P2O5 increased the marketable pod yield of snap bean at Jimma. Since, the experiment was conducted in a single location and season. So, repeating the experiment for more seasons and similar location would help us draw sound conclusive recommendations to the end users.

Effectiveness of Some IPM Packages Consisting of Chemical and Non Chemical Components for Suppressing Pod Borer and Aphid in Summer Country Bean

An experiment was conducted in the experimental farm of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur to evaluate the efficacy of IPM packages for suppressing aphid and pod borer of summer country bean BARI Seem-3. In case of aphid, among the different IPM packages, P4 [comprising mechanical control (hand picking) and 4 sprays of admire 50 SP (imidacloprid) @ 1ml l-1 of water at 7 days interval] had minimum inflorescence infestation (4.99), whereas untreated control plot P7 totally overturned. In case of pod borer, among the IPM packages, P5 [comprising mechanical control, hand picking with 4 sprays of ripcord 10 EC (cypermethrin) @ 1 ml l-1 of water at 7 days interval] ensured minimum inflorescence and pod infestation (by number and weight) and pod diameter with the lowest pest incidence (4.59 %). In consideration of the economic analysis of the different management packages for controlling pod borer of country bean, the highest BCR ratio (4.28) was recorded in the P5 [comprising mechanical control, hand picking with 4 sprays of ripcord 10 EC (cypermethrin) @ 1 ml l-1 of water at 7 days interval] followed by 3.76 in P6. However, based on marketable pod yield and BCR, hand picking with 4 sprays of ripcord 10 EC (cypermethrin) @ 1 ml l-1 of water at 7 days interval may be considered as the most effective option.J. Environ. Sci. & Natural Resources, 10(1): 109-115 2017

Efficacy of Potassium Salts of Fatty Acids in the Management of Thrips and Whitefly on Snap Beans

Snap bean farmers mainly rely on chemical pesticides to manage insect pests but the introduction of strict maximum residue levels (MRLs) by European markets poses a challenge to the use of pesticides. This has necessitated the search for alternative pest management options that do not result in harmful residues on produce. Therefore, this study was carried out to determine the efficacy of potassium salts of fatty acids as alternative to synthetic chemicals in management of snap bean pests. Field experiments were carried out in farmers’ fields in Mwea and Embu for two cropping cycles between July 2013 and January 2014. Potassium salts of fatty acids at 0.5%, 1% and 1.5% spray solution was compared with chemical pesticide confidor® (Imidacloprid) and farmers practice [Thunder® (Imidacloprid + Betacyfluthrin) and Karate® (Lambda Cyhalothrin). Population of thrips, whitefly, and yield of pest damaged pods, in addition to marketable pod yield was determined. Application of potassium salts of fatty acids at 1% and 1.5% significantly (P<0.05) reduced white fly and thrips populations by up to 54%. Weight of pest damaged pods was also significantly (P<0.05) reduced by up to 76% while the weight of marketable pod yield was significantly (P<0.05) increased by up to 112%. The results demonstrated that potassium salts of fatty acids are a viable alternative to synthetic chemical pesticides thereby enabling farmers to produce with acceptable residue levels that meet market requirements.

Management of Snap Bean Insect Pests and Diseases by Use of Antagonistic Fungi and Plant Extracts

Use of synthetic pesticides reduces the competitiveness of Kenyan snap bean pods due to stringent regulations by importers as a result of presence of chemical residues. This study was conducted to determine the effectiveness of local biopesticides in managing insect pests and diseases of snap beans. Field experiments were set up in farmer's field where Trichoderma spp. and Paecilomyce spp. and plant extracts from turmeric, garlic, ginger and lemon were applied weekly as foliar sprays. Plant extracts reduced the population of whiteflies and thrips by up to 58% and 41% while antagonistic fungi had a corresponding 30% and 18% reduction, respectively. Trichoderma spp. reduced severity of angular leaf spot (37.5%), rust (67%) and anthracnose (20.7%). Plant extracts and antagonistic fungi increased marketable pod yield by 25.6% and 17.3%, respectively. Results demonstrated that local environments are potential sources of biopesticides that can be exploited for integrated management of pests and diseases.

Increasing Fresh Edamame Bean Supply through Season Extension Techniques

Soybean [Glycine max (L.) Merr.], a legume native to East Asia contains up to 40% protein and 20% oil. Edamame, a popular vegetable soybean in East Asia, especially China and Japan, harvested at reproductive stages six and seven (R6 or R7) is gaining popularity in the US. Increased awareness of its nutritional quality through promotional campaigns and changing population demographics in the US have led to recent raise in US market demand for edamame. To meet the increasing market demand, frozen edamame from China and Taiwan has been imported. However, the quality of such imported product quickly deteriorates under frozen condition. The objective of this study was to determine whether off-season production systems and staggered planting of different maturity groups (MG) edamame cultivars during the planting season can extend the harvesting window for fresh beans. Four released edamame cultivars of different maturity groups (MG) were used: Gardensoy31 (MG III), Gardensoy41 (MG IV), Mooncake (MG V) and Randolph (MG VI). Total pod yield, marketable pod yield and seed quality traits including protein, oil and sucrose content of each cultivar were determined. The results indicated that early- and mid-spring planting of all MG varieties in the high tunnels allows for pod harvest starting in early July. Planting early in plasticcovered field followed by conventional planting in late-spring allowed harvest in mid-summer through early fall. While total and marketable pod yield differed among cultivars and production systems, seeds had comparable oil content (158 g kg-1) and protein and sucrose content range of 370-422 g kg-1 and 33-73 g kg-1 on dry matter, respectively. Use of season extension production techniques and soybean of appropriate MG increases harvest window from two weeks to several months.

Managing Weeds in Commercial Edamame Production: Current Options and Implications

Edamame, a specialty food-grade soybean popular among health-conscious consumers, is growing in popularity worldwide. Despite a well-developed soybean industry, most edamame consumed in the United States is imported from Asia. Considerable interest exists in growing edamame domestically; however, weed interference is a major problem, and until recently, only a single herbicide was registered for use on the crop. The objectives of this work were (1) to compare effectiveness of weed management treatments that utilize herbicides currently registered for use on edamame or that may be registered in the near future, (2) to determine the significance of edamame cultivar on performance of these treatments, and (3) to identify potential relationships between the crop and weed. Ten different weed management treatments were tested in three edamame cultivars over a 3-yr period. All weed management treatments increased marketable pod yield relative to the nontreated control, but only treatments with saflufenacil orS-metolachlor combinations were comparable to the hand-weeded weed-free treatment. Of the treatments studied,S-metolachlor followed by imazamox was among the greatest yielding, had the least weed density and biomass, and did not reduce crop population density. Also, cultivars differed in their weed-suppressive ability. Path analysis indicated certain relationships were consistent across cultivars, such as weed population density having a direct negative association with crop biomass; however, other edamame–weed interactions were not identical across cultivars. Although more improvements are needed, the vegetable industry is beginning to have nascent weed management options in edamame, which will likely reduce reliance on hand weeding and result in crop-production costs that are more competitive in the global market.

English

Snap bean (Phaseolus vulgaris L.) is one of the major vegetable crops in Ethiopia grown for export and local markets. The crop is mainly produced during the dry season under irrigation. Snap bean has higher price than other vegetables in local markets in Ethiopia; however, the high cost of production under irrigation restricts the majority of local farmers from taking this opportunity. The main objective of this research was to investigate the influence of nitrogen (N) treatment, cultivar and contrasting environments on pod quality of snap bean under rain fed conditions. Three N treatments (0 and 100 kg N ha-1, and Rhizobium etli[HB 429]) and eight snap bean cultivars were evaluated in a factorial experiment arranged as a randomized block design with three replications. The experiment was conducted at three locations (DebreZeit, Hawassa and Ziway) in 2011 and 2012. Applied N and rhizobium inoculant increased marketable pod yield by 43 and 18%, respectively. Cultivar Melkassa 1 had the greatest marketable yield, but had lower pod physical qualities than other cultivars. The highest zinc concentration in pods was obtained at Hawassa location. In conclusion, viable option for the production of high quality snap bean can be realised under rain fed condition using rhizobial inoculant as N source. These results open new opportunity for resource limited farmers in Ethiopia to produce snap bean with acceptable quality using rhizobial inoculation as N source under rain fed condition. Key words: Snap bean, cultivars, quality, rhizobium, nutrient concentrations.

Bio-efficacy of insecticides against aphid (Aphis craccivora Koch) infesting cowpea [Vigna ungiculata (L.) Walp.

Eleven different insecticides were evaluated for their efficacy against A. craccivora at Regional Horticulture Research Station, ASPEE College of Horticulture and Forestry, Navsari Agricultural University, Navsari, Gujarat during Rabi season of the year 2013-2014. The treatment imidacloprid 0.005 per cent (0.19 aphid index/plant) was found to be most effective followed bythiamethoxam 0.01 per cent (0.33 aphid index/plant). Verticillium lecanii 0.40 per cent (0.58 aphid index/plant), azadirachtin 0.002 per cent (0.62 aphid index/plant) and dimethoate 0.03 per cent (0.77 aphid index/plant) were the next in order. The highest marketable pod yield (30.37 q/ha) and maximum per cent increase in pod yield of cowpea over control (84.28 %) was recorded from the plots treated with thiamethoxam 25 WG @ 0.01 per cent.

Yield and Quality of Vegetable Soybean Cultivars for Production in North Dakota

Vegetable soybeans (Glycine max), the same species as field-dried soybeans, have similar production requirements and good market potential for commercial producers in upper midwestern United States. Five vegetable soybean cultivars were tested for yield and quality characteristics and to assess the necessity of field irrigation during 2003 and 2004 in North Dakota. Cultivars of different maturity dates were evaluated for stand densities, pod production, seed weight, and marketable yield. Total marketable yields varied between the years, ranging from 5773 to 10,118 lb/acre. Lower yields in 2003 were attributed to significantly lower population stands caused by poor germination conditions. `Envy', the earliest maturing cultivar, produced a significantly smaller seed size, while `Sayamusume' produced a greater seed size than the other cultivars both years. `Butterbean', `IA1010', and `IA2062' yielded greater percentages of three-bean pods than the other two cultivars each growing season. Irrigation did not increase the marketable pod yield or the quality variables examined each season; thus it appears that rainfall during the growing season may be adequate for vegetable soybean production in this region.

The effect of N fertilizer strategy on N 2 fixation, growth and yield of vegetable soybean

Vegetable soybean ( Glycine max) is a lucrative cash crop predominantly grown in Japan, Taiwan, China, Thailand, and Vietnam. Although soybean has the capacity to satisfy a large proportion of its own nitrogen (N) requirements via N 2 fixation, farmers are recommended to apply several side-dressings of fertilizer N during growth in the belief that this will maximize pod yield. A field experiment was conducted in northern Thailand to evaluate the effect of six different N fertilizer management strategies on crop growth and marketable pod yield of vegetable soybean and to assess the impact of fertilization on the potential carry-over of residual fixed N remaining after harvest. A vegetable soybean crop was supplied with 25 kg N ha −1 ammonium sulphate as starter N at sowing, then areas of the crop either received no further fertilizer N, or received one (50 kg N ha −1), or two (50 + 25 kg N ha −1) urea top-dressings at different stages of vegetative and/or reproductive growth. The field trial demonstrated that the appropriate timing of N fertilization could improve both crop growth and pod yield. Crop biomass was increased by 11 to 16% and pod yield improved by up to 44% if starter N was followed by a single top-dressing at either early vegetative growth or at flowering. However, there was no additional benefit from the standard farmer practice of supplying two top-dressings prior to flowering. However, if an early vegetative application of fertilizer N was followed by a second dressing either during flowering or pod-fill a further 20% increase in marketable pod yield was achieved. The effect of fertilizer N on soybean's capacity to fix N was complex. The proportion of plant N derived from N 2 fixation (Pfix) was highest when only starter N 2 was applied (seasonal average of 84% of crop N 2 coming from N 2 fixation). Any further top-dressing with N-fertilizer depressed nodulation and Pfix, but also increased crop growth so that amounts of N, fixed were similar for most fertilizer treatments (adjusted to account for below-ground N: 149 to 153 kg N ha −1 cf 147 kg N ha −1 fixed in the presence of starter N alone). However, N 2 fixation was significantly depressed by the farmer practice of top-dressing N twice before flowering (117 kg fixed N ha −1, and was highest when fertilizer N was supplied during a period of peak N demand at pod filling (180 kg N ha −1). Between 53 and 92 kg N ha −1 was removed from the crop in marketable pods. But since N 2 fixation remained the dominant N source for crop growth in all treatments, substantial amounts of fixed N (64 to 91 kg of fixed N ha −1 were estimated to remain in leaf, stem and root residues after harvest. However, the potential N benefit from including vegetable soybean in a cropping sequence disappeared if the above-ground residues were removed from the field as is the common practice in many Asian farming systems.